I think you are looking at the SDS EF86 board that was sold by Triode Electronics. It resembles this scan of the board, though not precisely. http://www.quadesl.com/pdf/st70board_ef86.pdf I have the 6AU6 version. It breaks the original pentode/triode assembly up from 2 tubes to 3 by using a 12AU7 in the middle as a triode phase splitter with the outside tubes the EF86's as the pentode amplifiers. The sound from this board is similar to the original.